How to Troubleshoot and Fix U1120 Jeep DTC Code?

Do you want to have a safer driving experience all the time when you drive your Jeep? Then, it’s essential that you must get rid of the U1120 Jeep code as soon as it is stored.

No need to be worried, we will discuss every bit of detail: what are the reasons behind the code, and how to fix them. Keep reading to find out more!

What Does U1120 Jeep Code Mean?

The Anti-brake locking (ABS) system on any vehicle dominates in ensuring improved stability. In the case of Jeep, the fact remains the same. 

But, when the powertrain control module (PCM) of Jeep does not get the message from the ABS module the code U1120 takes place. 

The ABS control module receives a signal over the ‘CAN C bus’ communication channel to send the information from the wheel speed sensor to the powertrain control module. 

But due to a few issues, the information from the wheel speed sensor may not reach PCM. When you install the scan tool, you will see ‘Code U1120-Lost Wheel Distance Message’.

• U = Network & vehicle integration
• 1 = A generic manufacturer-specific code derived from the SAE standard. 
• 1 = Fuel and air metering
• 20 = Specific fault code 00-99 ( PCM does not receive signal) 

U1120 Code: What Causes Lost Wheel Distance Message on Jeep?

The Anti-brake locking System consists of several essential components. Any issue related to this system can be caused by the malfunctioning parts that come into play to function the system properly. 

Needless to say, even if a single component becomes bad, the whole Anti-brake locking system (ABS) can be affected. Some possible causes of code u1120 are;

1. Open or shorted harness of the Anti Lock Braking System (ABS)
2. Anti Lock Braking System (ABS) insufficient electrical connection. 
3. Faulty Anti-lock Brake Module. 
4. Bad wheel speed sensor.
5. Faulty Can C bus circuit.
6. Bad powertrain control module.

Therefore, for the reasons above, the powertrain control module may not receive the speed signal. 

And after having an in-depth analysis and coming in touch with a good number of Jeep owners, we believe checking and fixing the causes above will help you deal with the U1120 code.

Read Also: How to Troubleshoot and Fix P0507 Jeep Commander DTC Code?

How to Troubleshoot & Fix U1120 Jeep Code?

Once you know the possible causes of the code, you are not supposed to face that level of difficulty when troubleshooting the code. 

But you might need some technical knowledge to do the job yourself. However, let’s find the ways you can follow to eliminate the code.

1. Check and Repair/Replace the Open or Shorted Harness of the Anti-Brake Lock System (ABS) Module

Needless to say, the Anti-brake Lock System (ABS) Module in your Jeep is a critical electrical component. 

And when it comes to making the most out of the module to ensure stability, control, and safety, the component needs to function well. Besides, it can malfunction and cause significant risks when driving your Jeep.

The shorted or open harness is one of the core reasons the Anti-brake Lock System (ABS) Module can malfunction. 

With the help of the wiring harness, the Anti-brake Lock System (ABS) Module communicates with different components in the ABS, including the PCM. 

And so, if the wiring harness is shorted to open, the communication process is disrupted.

In most cases, the wiring harness can be broken due to extreme corrosion (Or other physical damages) and shorted due to current overloading. 

So, check the wiring harnesses of the Anti-Brake Lock System (ABS) and repair and replace them based on their conditions. But it is always better to diagnose the issue with a professional mechanic.

Read Also: How to Troubleshoot & Fix P0394 Jeep Wrangler DTC Code? Comprehensive Explanation!

2. Anti-Lock Braking System (ABS) Insufficient Electrical Connection

Next, As the Anti-lock brake system (ABS) is an electric component, it needs proper electrical power to communicate with other components of the Anti-lock brake system (ABS). 

And if there is a lack of electricity, the system is supposed to malfunction. Therefore, the message the Anti-lock brake system (ABS) module gets from the wheel speed sensor usually turns out to be incorrect. 

Due to a lack of electrical connection, the Anti-lock brake system (ABS) module can’t find ways to connect with the rest of the Jeep components. 

And how can you ever expect the Anti-lock brake system (ABS) to work correctly in such a case? 

In most cases, loose connection brings the issue of poor electrical connection in the Anti-lock brake system (ABS). 

Here, the solution is to check what causes the poor electrical connection of the Anti-brake Lock System (ABS) in your Jeep. 

If you find any loose connection wires, you need to fix them. Chances are the poor electrical connection, in this case, is due to damaged wiring. The solution of which is mentioned above.

Read Also: How to Troubleshoot & Fix P0507 Jeep Grand Cherokee Code?

3. Check and Replace the Faulty Anti-lock Brake Module

Let’s say there are no such issues regarding bad wiring of the ABS and poor electrical connection. However, extreme chances are there the anti-lock brake module itself can go bad or become defective. 

And if this happens, the powertrain control module of your Jeep has a reason to store the code U1120. 

Due to a bad anti-lock brake module, the powertrain control module of your Jeep can’t get the appropriate data from the wheel speed sensor. 

And thus, your Jeep becomes unable to function the anti-lock brake system, which causes safety hazards for your Jeep, reducing the chances of stability control. 

Now you know the solution. What you should do is check the faulty anti-brake lock module of your Jeep. 

And if the anti-brake lock module comes out as faulty, you need to replace it without a second thought. 

This is because repairing the components won’t provide you with real value. To replace the anti-brake lock module, you must pay approximately $500-$600.

4. Check and Replace the Bad Wheel Speed Sensor

If you can find any issues with the anti-brake lock system in your Jeep, the very component you need to check is the wheel speed sensor. But why will you do so? 

This is because the wheel speed sensor is the component from which the anti-brake lock module gets data about the wheel speed. Now you know what can happen if the wheel speed sensor goes bad. 

If the wheel speed sensor is not up to the mark, it is not supposed to function correctly. To be precise, the anti-brake lock module won’t be able to get correct data from the component. 

And if this happens, the powertrain control module considers the wheel speed data from the ABS as a lost wheel speed message, and the U1120 occurs.

Now what wrong can happen with the wheel speed sensor in your Jeep? In most cases, there might be physical damage to the wheel speed sensor. 

At the same time, the wheel speed sensor can be highly corroded. So, you need to check the sensor carefully. If the sensor is bad, you should replace it, which will cost $124-$150.

Read Also: How to Troubleshoot and Fix the P0457 Jeep DTC Code?

5. Check and Replace the Faulty CAN C Bus Circuit

The CAN C bus circuit is the connection line in which the data from the wheel speed sensor data is transmitted via the anti-brake lock module of your Jeep to the powertrain control module. 

Now, even if there is no issue with the wheel speed sensor or the anti-brake lock system, problems with the CAN C bus Circuit can often cause the code U1120 on your Jeep.

As the Can C bus allows various components in a vehicle to communicate with each other, it can malfunction if there is any electrical issue. But what’s wrong can happen with the Can C bus circuit? 

In most cases, it can be affected by electromagnetic interference. Or, chances are there is physical damage and a wiring connection problem.

To solve the issue of the bad CAN C bus circuit issue, you must carefully check it at the very beginning.

However, it is better to let the mechanic. If the mechanic thinks there is an issue with the Can c bus circuit, the mechanic will repair or replace it. 

6. Check and Fix the Bad Powertrain Control Module

After checking all the components mentioned above, if you can’t fix the code, do check the powertrain control module.

The wheel speed sensor data might be correct, but as the powertrain control module is supposed to be bad, it finds the data incorrect. 

One of the core responsibilities of the powertrain control module in your Jeep is to process data from different sensors. 

Now, how can you expect it to process the data properly if it becomes defective? No way whatsoever!

The PCM can go bad for many reasons. Among them, the prominent causes are physical damage, electrical problems, overheating, and more. Therefore, you need to check the issues when inspecting the powertrain control module. 

Once you do a deep check of the powertrain control module, next if it is faulty, you need to replace it. 

But it will be better to go with an expert mechanic before doing so. Replacing the PCM can be costly, estimated at around $500-$600.

Read Also: How to Troubleshoot and Fix the P1491 Jeep DTC Code?

Frequently Asked Questions

We’ve sorted out some of the questions Jeep owners often ask regarding the code U1120. And for you, we find that urgency to answer those questions below.

Final Thoughts

Don’t panic if you see the code U1120 on your Jeep. Instead, it is better to take troubleshooting steps as early as possible and do it carefully. 

Besides, don’t just randomly replace any component without having a deep inspection. Furthermore, be more careful about your Jeep to avoid any issues.